Effect of the semi‐fluorinated chiral alkane on the formation of the antiferroelectric phase

Two structurally similar homologous series of chiral liquid crystals derived from semi‐fluorinated and non‐fluorinated alkanes positioned at a chiral terminal chain have been synthesized and characterized by differential scanning calorimetry, polarizing optical microscopy and electric‐optical measurements. It was found that there are two semi‐fluorinated materials in the series I‐m (m = 8, 10), that exhibit ferroelectric SmC∗ and antiferroelectric phases. The corresponding non‐fluorinated materials II‐m (m = 8, 10), however, display only the SmC∗ phase, suggesting that the fluorinated materials encourage the formation of the antiferroelectric phase. The spontaneous polarization (P s) and apparent tilt angle (θ) were measured, showing that the semi‐fluorinated materials have higher P s and θ values than non‐fluorinated materials at any reduced temperature below the SmA∗–SmC∗ transition.